Gear-molding process



July 2 192.9- E. G. DANIELsoN 1.719.290v

, GEAR MoLDING SPRocEss y Filed June 8; 1927 FIIE 4 FIE-E FIELE- 2/ 2f@ 2Q t A TKTORNEYS.

' `invention.

hasta July 5192s. -i fi* G. DANIELSQN, F SAN FRANCISCO, CALIFORNIA.

ema-uomini; raocnsa application mea rane s, naar. sei-iai no. isms?.

This invention relates generally to a process of manufacturing gears vfrom moldable v material, such as a phenolic condensate product, and to a new articleof manufacture resulting from the same.

Itis an object of this invention to devise a 1 novel vprocess of forming die cast gears from ber reinforced moldable material. It is a further object of this invention to 1o devise a process which will materially cheapen the cost of'manufacturing gears of moldable material having fiber reinforced teeth. v l

It is a further object of this invention to l5 devise a novel process of forming gear teeth in moldable material, which will provide liber reinforcing threads following the general contour of the teeth.

It is another object of this invention to devise a new typer of molded gear resulting from the process of this invention.

Further objects of this invention will apy pear from the following description in which Ihave set forth the preferred embodiment of my invention. It is to be understood that the appended claims are to be accorded a range of equivalents consistent with the state of the prior art. Y i

Referring to the drawing: Fig. 1 is a view showing the character of the reinforcing fabric which I prefer to emply in the process of this invention.

ig. 2 illustrates the manner in which the fabric strip shown in Fig.1 is wound upon a mandrel to form a ring of gum impregnated reinforcing material.

Fi 3 is a view showing a ring of impregnatereinforcing material after it has been removed from the mandrel shown in Fig. 2.

Fig. 4 is a plan view of the die emplo ed in this rocess, with the ring shown in ig. -3 positioned adjacent the gear teeth of the die.

Fig. 5 is .asectional view taken along the line 5-5 of Fig. 4, illustrating the manner in which the materials forming theV gear are assembled preparatory-to the fipal steps of the fproeess. Fig.

' illustrating the. step of compressing the body of the ar.

' A Fig. is a detail, view illustrating a. com- .plete gear resulting from `the process of this In the manufacture gears from moldable pro reinforced by impregnated fabric.

" made of e is view of the die similar to Fig. 5,-

material, it has been common to employ layers or laminations of fabric for reinforcing the teeth. In manufacturing such gears the layers of fabric are generally impregnated in some suitable binder, such as a phenolic condensate gum, and are then assembled in layers parallel to the gear faces. By the application of heat and pressure, these layers of impregnated fabric are then bonded together to form a composite teeth must then be milled to the peripheral surface of the resulting blank. vIn some cases themilling operation is made less expensive by roughly formin v the gear teeth outlines in each layer of fa ric, so that the finished 1 blank before the milling operation will have roughly formed teeth., In this invention I pose to entirely obviate the necessity of milling the teeth, and at the same time provide a gear in which the teeth are adequately The process of thisv invention may be characterized by the fact @that instead of building up the entire gear body of laminatioiis of ieinforcing fabric, the fabric is assembled to forman annular ring which is then. pressed into die teeth; For exam le in Fig. 1 there is shown a strip 10 of suitable fabric such as is ordinarily lein loyed in reinforcing objects strip is a out the same width as the Width of the face of the gear which it is desired to manufacture, and preferably has a pronounced warp extending longitudinally the strip. For example threads 11 constituting the warp, are much heavier than the threadsV 12 which form the Woof of the fabric.

gear body. VThe gear This stri is impregnated or dipped in a suiti able bin g material, such as what is commonly known as phenolic condensate gum, and is then wound upon a mandrel 13 such as shown in Fig. 2. Several layers of the fabric are wound about the mandrel so as to form a substantial ring of reinforcing material. For a reason which will presently be apparent, it is desirable to provide this vring with corrugations. One convenient way to form such corrugations is to provide the face of the mandrel 13 with corrugations 14. as shown, and a corrugated idler wheel 16 maybe provided to insure forming similar corrugations in the fabric as it is wound upon the mandrel. After a sufficient number of layers have been applied, the fabric is slipped olf in the form of a ring 17 such as shown in Fig. 3, this ring being provided with the corrugations 18.

The subsequent steps of the process are performed in a die such as shown diagrammatically in Figs. 4, and 6: This structure utilizes a die block 21 having formed therein the die gear teeth 22 which are complementary to the gear teeth desired upon the final product. The ring 17 is constructed of such size that it will slip within the die with its -l outer periphery,-or inner periphery in case of an internal tooth gear,adjacent the die teeth 22. After inserting the ring 17 in osition, a slu 23 of some suitable molda le material, suc as a suitable phenolic condenj sate product, is positioned within the die belowthe plunger 24. In case a central pin'26 is provided in the die for forming a central aperture in tle'nished product, it is obvious that slug 23 should also be provided with a central aperture 27. The slug is preferably preheated to a moldable or plastic temperaf ture before insertion in the die, and the entire die is also vpreferably heated so that the material is formative und'er` pressure. Plunger 24 is then forced downwardly to compress the Aslug 23, and as the vertical dimension of this slug is decreased it naturally expands'in a radial direction against the inner periphery of the reinforcin ring 22. During the final-movement of t e plun er relatively great pressure is applied to s ug'v 23, and this pressurepushes radially against the inner periphery of ring 17 to force the' ring into the die teeth 22. The corrugations 18 provide suiicient length of material in the ring so that the gum dipped fabric will conform to the contour of the die teeth Without stretching of the fabric threads. At this time the layers of fabric are also forced together under highpressure so that the reinforcing ring becomes one solid mass of composite material, and is also effectively bonded to the material of the slug 23.

The fnal-product when removed from the die will be somewhat as shown in Fig. 7. Thus the slug 23 will have formed a body 3.0, and the ring 17 will have formed a peripheral portion 28 of fabric reinforced moldable material.A Gear teeth 29 are accurately impressed in the peripheral ortion 28, and at east the outer layers of abric 31follow substantially the contour of the gear teeth. It is obvious that this arran ement of the fabric effectively reinforces t e gear teeth against bending adjacent their bases, where normally the heavier reinforcing threads 12 run sub- .stantiall parallel to the gear faces, the bearthe gear teeth are 'apt to break. As

ing sur aces of the gearare formed of impregnated fabric rather than by the phenolic condensate product alone, and therefore the gear is more silent in operation than the ordinary type of composite gear. In other words the particular manner in which I reinforce the gear teeth causes a cushioning eiiect in addition to providing adequate reinforcing.

It is obvious that a gear constructed according to this process may be manufactured much more cheaply than the usual type of molded gear which requires subsequent milling. A minimum amount of reinforcing fabric is'required and therefore only a small amount'of phenolic condensate gum, which is used in impregnating this fabric, is necessary. This phenolic condensate gum is relatively expensive compared to ordinary molding materials, and is a substantial item in the cost of gears which require a large amount of gum dipped reinforcing fabric. The greater portion of the gear of my invention, may be formed of a vrelatively cheap moldable inaterial, which however provides sucient strength to carry the torsional stresses placed upon the gear.

It is obvious that the above process is capable of many modifications. For example the corrugations in the ring 17 may not be applied While winding the fabric strip 10, but may be applied to the ring at any time before insertion in the die. The nature of these corrugations is not material, as their only function is to provide sufficient length so that the fabric may be readily forced into the die y teeth. It is preferable however to have the pitch of these corrugations about equal to the pitch of the gear teeth. It is also to be under stood that the process is applicable to a variety of gears, such for example as internal tooth gears and gear racks, as Well as the ordinary types of gear wheels and pinions.

I claim: y

1. A processl of forming a gear which utilizes a ring of binder impregnated reinforcing material for forming the peripheral portion of the wheel and a moldable substance for forming the gear body, said process comprising applying a molding pressure to said substance whereby it is caused to ress radially upon one peripheral surface o the ring .to force said ring into adjacent die teeth.

2. A process of forming a gear having a body of moldable substance and a eripheral portion of moldable fiber reinforced material, said process comprising forming a corrugated ring of said material, placing said ring within a die having annular gear teeth complementary to those desired on the finished gear, and molding said body about one peri heral surface of saidl ring by application o pressure to the moldable substance, said pressure being sufficient to force said ring into the die teeth, said corrugations serving to provide a ring of suiiicient peripheral dimension whereby it may conform to the die teeth without material stretching.

3. lA process of making a gear having a body of a phenolic condensate product and a peripheral portion of fiber reinforcing masterial impregnated with a phenolic condensate gum and formed to provide gear by application'of ressure to the same, said teeth, said process comprising forming acorpressure being s cient to force said ring rugated ring of said gum impregnated mainto the die teeth a'nd to form an efective 10 terial, placing said ring Within a die having bond between the body and said ring.

5 annular gear teeth complementary to those In testimony ywhereof, I have hereunto set desired of the finished gear, and molding said my hand. body about one peripheral surface of the ring ERNEST G. DANIELSON. 

